Discussion about the ending and the vault

Do all vault give some degree of foresight? Or is the timekeepers vault uniquely a time travelling vault?

Left a bit confused after the ending, seeing what seems to be a future Lilith and a structure which seems to be somewhat of a shrine to sirens.

When Jack looks at the vault key in BLTPS he starts to see the future with the destroyer as well. So I just wanted to ask the community what you think about the timekeepers vault, what it is, why he was guarding it and if that was a unique vault?